"We don't know which lifeboat the biscuit came from but there are no other Titanic lifeboat biscuits in existence to my knowledge.

"It is incredible that this biscuit has survived such a dramatic event - the sinking of the world's largest ocean liner - costing 1,500 lives.

"In terms of precedence, a few years ago a biscuit from one of Shackleton's expeditions sold for about £3,000 and there is a biscuit from the Lusitania in a museum in the Republic of Ireland.

"So we have put an estimate of between £8,000 and £10,000 which makes it the most valuable biscuit in the world."

The Titanic sank after striking an iceberg on April 14 1912 during its maiden voyage to New York from Southampton.

The biscuit will be sold alongside the Fenwick archive - a unique photographic history of the rescue of the survivors from the Titanic.

Mr Fenwick and his newlywed wife Mabel were embarking on a three-month honeymoon trip to Europe and had reached New York on April 11 1912, little knowing that four days later the Carpathia would be the saviour of over 700 survivors from the Titanic.

The collection is being sold via direct descent of the Fenwicks and the photographic negatives included offer a unique snapshot into the rescue, showing the first sightings of the lifeboats, survivors on the Carpathia, their arrival in New York and even the SS Californian arriving at the scene of the rescue.

The photograph of the SS Californian has been described "one of maritime history's most dramatic photos".

The story of the Californian is one the most controversial in Titanic's tragic loss as the captain was blamed for not reacting more quickly to the disaster.

Also being sold as part of the collection is an unpublished account of the rescue of the survivors written by Mr Fenwick.

The entry for April 15, hours after the Titanic sank states: "5am. Awakened by hearing man's voice Titanic gone down. We are rescuing passengers and are surrounded by icebergs. This is time to be up and doing. Going on deck we found boats at our side crowded with those rescued plus other boats coming from all quarters, just beyond and on all sides of us... were the 'bergs."

The log goes on to detail other important events including the Carpathia's arrival in New York and the disembarkation of the Titanic survivors.

Mr Aldridge added: "The Fenwick archive is arguably the definitive photographic archive of negatives relating to the rescue of the surviving Titanic passengers and crew.

"The camera the couple were carrying was able to chronicle the momentous events that followed and provide a unique record of the events that unfolded."